WASHINGTON (CNN) -- In one of the shortest session in its history, the Senate's final session of the year lasted a total of 12 seconds Monday.

Democrats kept the Senate in session over the holiday season.

Only one senator, Democrat Jack Reed of Rhode Island, was in the chamber to gavel open the Senate and adjourn it until January 3.

Monday's event was the latest in a series of "pro forma" sessions the Senate has called. Pro forma means "for the sake of formality" and these micro sessions are part of the last political scuffle between the White House and the Democratic-led Congress.

Democrats are keeping the Senate in session to block President Bush from making any recess appointments. During congressional recesses, a constitutional mechanism allows the president to fill top government posts for up to one year without Senate confirmation.

Nearly all the senators left the Capitol for the Christmas holiday nearly a week and a half ago, but only one senator is needed to keep the Senate in session.

During the session last week, Sen. Jim Webb, D-Virginia, opened and then immediately gaveled the Senate session to a close. Wednesday's session lasted for 11 seconds. In all, he spent 57 seconds in the chamber.

Senate Majority Leader Harry Reid, D-Nevada, announced December 19 that he would keep the Senate open with a series of pro forma sessions through mid-January.

Talks had just broken down with the White House on a deal that would have allowed the president to make dozens of those appointments if he agreed not to appoint one controversial official, Steven Bradbury, as the permanent head of the influential Office of Legal Counsel at the Justice Department.

Bush declined to accept the Democrats' offer, and Reid refused to approve Bradbury because of concerns about his involvement in crafting legal opinions for the administration on interrogation techniques of terrorism suspects.

Similar sessions were conducted over the Thanksgiving recess.

Other Democrats -- including Sens. Edward Kennedy of Massachusetts, Byron Dorgan of North Dakota, Mary Landrieu of Louisiana, Ben Cardin of Maryland and Chuck Schumer of New York -- will share the duty of presiding over the "pro forma" sessions next month.E-mail to a friend